# std::return_temporary_buffer

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< cpp‎ | memory

Defined in header `<memory>` |  |
template< class T > void return_temporary_buffer( T* p ); |  | (deprecated in C++17) (removed in C++20)

Deallocates the storage referenced by p.

If p is not a pointer value returned by an earlier call to std::get_temporary_buffer, or has been invalidated by an intervening `std::return_temporary_buffer` call, the behavior is undefined.

### Parameters

p | - | the pointer referring to the storage to be declloated

### Return value

(none)

### Exceptions

Throws nothing.

### Example

Run this code

    #include <algorithm>
    #include <iostream>
    #include <iterator>
    #include <memory>
    #include <string>

    int main()
    {
        const std::string s[] = {"string", "1", "test", "..."};
        const auto p = std::get_temporary_buffer<std::string>(4);
        // requires that p.first is passed to return_temporary_buffer
        // (beware of early exit points and exceptions), or better use:
        std::unique_ptr<std::string, void(*)(std::string*)> on_exit(p.first,
        [](std::string* p)
        {
            std::cout << "returning temporary buffer...\n";
            std::return_temporary_buffer(p);
        });

        std::copy(s, s + p.second,
                  std::raw_storage_iterator<std::string*, std::string>(p.first));
        // has same effect as: std::uninitialized_copy(s, s + p.second, p.first);
        // requires that each string in p is individually destroyed
        // (beware of early exit points and exceptions)

        std::copy(p.first, p.first + p.second,
                  std::ostream_iterator<std::string>{std::cout, "\n"});

        std::for_each(p.first, p.first + p.second, [](std::string& e)
        {
            e.~basic_string<char>();
        }); // same as: std::destroy(p.first, p.first + p.second);

        // manually reclaim memory if unique_ptr-like technique is not used:
        // std::return_temporary_buffer(p.first);
    }

Output:

    string
    1
    test
    ...
    returning temporary buffer...

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
LWG 2072 | C++98 | the storage allocated by std::get_temporary_buffer could be deallocated multiple times | the behavior is undefined in this case

### See also

get_temporary_buffer (deprecated in C++17)(removed in C++20) | obtains uninitialized storage (function template)

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